It will now finally look like a sofa again. I think the video is clear enough how you can tension the fabric, that is with substaples. You keep your staplegun a bit sluntwise so that only one leg comes into the wood. Always work from the center. The corners are the last thing you do. When the fabric is completely tensioned and you like it, you replace the substaples with final staples. Certainly it is extra work, but if the fabric is not properly tensioned, it is much easier to remove the staples. Therefore, substaples.
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